Apparatus and method for managing dormant state in a wireless packet data system

ABSTRACT

A wireless packet data system efficiently manages a location of a packet call in a radio environment. A mobile station transmits a location registration message to a target BSC when moving to the target BSC adjacent to a source BSC. Upon receipt of the location registration message, the target BSC transmits a location update message for updating a location of the mobile station to a centralized database. Upon receipt of the location update message, the centralized database updates dormant state information for the mobile station to connect the target BSC to the source BSC. The centralized database transmits a location update result message indicating complete update of the dormant state information to the target BSC.

PRIORITY

[0001] This application claims priority to an application entitled“Apparatus and Method for Managing Dormant State in a Wireless PacketData System” filed in the Korean Industrial Property Office on Aug. 19,2000 and assigned Serial No. 2000-48180, the contents of which arehereby incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to a wireless packet datasystem, and in particular, to an apparatus and method for managing alocation of a packet call in a radio environment.

[0004] 2. Description of the Related Art

[0005] In general, a wireless packet data system is included in a mobilecommunication system, and refers to a system for transmitting data inthe form of a packet through a wireless network. For example, the systemincludes a CDMA (Code Division Multiple Access) system, a PCS (PersonalCommunications Services) system and a future mobile communication systemsuch as a CDMA-2000 system and a W-CDMA system, standardizations ofwhich are under way.

[0006] Meanwhile, the wireless packet data system manages informationpertaining to a mobile in service in order to provide a packet callservice. Here, since the “mobile” refers to a mobile station (MS) not abase station (BS), the information on the mobile must necessarilyinclude location information of the mobile. Further, a base stationcontroller (BSC) constituting the wireless packet data system processespacket data incoming to and outgoing from the mobile according to themanaged location information of the mobile.

[0007] The location information is managed in different ways accordingto states of the mobile. In an active state and a control hold statewhere certain channels are established, the location information ismanaged through a handover. That is, since the mobile performs ahandover using a dedicated signaling channel (dsch), a dedicated trafficchannel (dtch) and a dedicated MAC (Medium Access Control) channel(dmch), it makes the transition from one state to another state whilemaintaining one or more channels to the BSC during a handover.Accordingly, the movement of the mobile in the above states can becontinuously traced by the BSC.

[0008] However, if the mobile enters a dormant state where transmissionand reception of the traffic is not performed because no packet data istransmitted for a predetermined time, there exists no connection betweenthe mobile and the BSC, making it impossible to manage the location inthe same way as done in the active state and the control hold state.

[0009] The dormant state means a state where such traffic as voice andpacket data is not generated in a state where a radio channel isestablished. When the dormant state occurs, the wireless packet datasystem manages a location of the packet call in the dormant state toprepare for later resumption of the traffic. For this reason, theconventional wireless packet data system proposes the following fourplans of managing a packet call in the dormant state, and adopts one ofthem.

[0010] In a first proposed plan, a home location register (HLR) and avisitor location register (VLR) take exclusive charge of the locationmanagement of a call, and a base station system (BSS) deletes allinformation on a call that entered the dormant state. In this case, whena packet call in the dormant state requests transmission of the packetdata, the same process as a normal new call setup process is performed.That is, an initial call setup process, a registration process and anauthentication process are all performed. As a result, an exchange ofradio messages due to the call setup process increases a load on an RF(Radio Frequency) stage, and brings about processing loads on theVLR/HLR/AC (Authentication Center) due to the registration andauthentication processes. In addition, performing the complicated callsetup process causes an increase in a packet buffering time, thusincreasing a delay time. In particular, it is difficult to trace alocation of the mobile existing in the dormant state, so that a pagingload may increase when there is a request for an incoming call to themobile from the network.

[0011] A second proposed plan is to compensate the first proposed plan.This plan provides a plurality of the VLRs/HLRs in order to decrease theprocessing loads of the single VLR/HLR performing the locationmanagement. In this plan, location management of the mobiles is notprocessed in the single VLR/HLR, but the mobility of all the mobiles isprocessed by a plurality of the VLRs/HLRs on a load shared basis.Therefore, the BSCs determine the VLR/HLR managing the locationinformation of the corresponding mobile using an identifier (ID) of themobile, and then acquire the mobile information through thecorresponding VLR/HLR. However, as the second plan is fundamentallyperformed in the same procedure as the first plan, the second plan issomewhat effective in decreasing the load on the VLR/HLR but still hasthe other disadvantages.

[0012] A third proposed plan stores an ID of a source BSC initiallyaccessed by the mobile for a packet data service until the call isreleased, and performs location management and dormant state managementof the corresponding mobile by utilizing the stored information. Thatis, when the mobile is activated in the dormant state, the mobileprovides the ID of the initially accessed BSC (source BSC) to a newlyaccessed BSC (hereinafter, referred to a “target BSC”). In this case,when processing a registration message of the mobile, the target BSC canrapidly access a dormant state database (DB) of the mobile whose packetservice is activated. However, to this end, the radio interface standardmust be changed undesirably. That is, the message format must be changedsuch that the mobile can transmit the ID of the source BSC to the targetBSC.

[0013] A fourth proposed plan is to construct a small-scale VLR notunlike the VLR/HLR connected to a mobile switching center (MSC), andarrange the small-scale VLR in a network where a new server exclusivelymanages the dormant state of the mobiles. This small-scale VLR isconstructed as a BSC. That is, the small-scale VLR is arranged in anetwork where a separate server is constructed as a BSC, and the BSCsacquire and update the information on the data service call in thedormant state from the separate server. In this case though, it isnecessary to construct separate hardware, and guarantee theVLR/HLR-level safety to the new device. In addition, from a viewpoint ofthe BSCs , there exists an overhead that the BSCs should simultaneouslyregister all the registration messages in the MSC and the separateserver as well.

SUMMARY OF THE INVENTION

[0014] It is, therefore, an object of the present invention to providean apparatus and method for effectively embodying a packet data servicewithout a separate device and modification of the radio interfacestandard in a wireless packet data system.

[0015] It is another object of the present invention to provide anapparatus and method for managing mobiles in a dormant state in a BSC,thereby enabling termination of a packet call to the mobile and rapidreconnection.

[0016] It is further another object of the present invention to providean apparatus and method for enabling reconnection to a previous PPP(Point-to-Point Protocol) access point in a BSC, upon receipt of a calloriginated from a mobile in a dormant state.

[0017] It is yet another object of the present invention to provide anapparatus and method for readily performing a service for managing amobile in a dormant state even though traffic through an IP (InternetProtocol) network becomes larger than a capacity of a voice call.

[0018] It is still another object of the present invention to provide anapparatus and method in which an error occurred in a certain BSC doesnot affect a service performed by another BSC.

[0019] It is still another object of the present invention to provide anapparatus and method in which BSCs have search and addition/deletionfunctions for effective database management by maintaining informationon the maximum number of mobiles in the dormant state.

[0020] According to one aspect of the present invention, there isprovided a method for storing dormant state information of mobilestations in a dormant state where no packet data is exchanged with anexternal packet network, in a centralized database connected to a packetdata switch, and updating the dormant state information stored in thecentralized database in association with the mobile stations when amobile station in the dormant state moves to a, target BSC adjacent to asource BSC in a wireless packet data system including a packet dataswitch node (PDSN) for connecting the external packet network to themobile stations through the packet data switch and the source BSCconnected to the packet data switch. The method comprises the steps oftransmitting a location registration message from the mobile station tothe target BSC when the mobile station moves to the target BSC adjacentto the source BSC; upon receipt of the location registration message,transmitting a location update message for updating a location of themobile station, from the target BSC to the centralized database; uponreceipt of the location update message, updating dormant stateinformation for the mobile station by the centralized database so as toconnect the target BSC to the source BSC; and transmitting a locationupdate result message indicating complete update of the dormant stateinformation from the centralized database to the target BSC.

[0021] Preferably, the dormant state information includes an identifierof the mobile station, location information of the mobile station, alast registration time of the mobile station, and a source BSC ID of themobile station.

[0022] Further, the dormant state information includes identifiers forconnections used to exchange packet data of the mobile station in thedormant state, a temporary identifier temporarily assigned to the mobilestation, a service option and service configuration.

[0023] Preferably, the location update message includes an identifier ofthe mobile station, and location information of the mobile station.

[0024] Preferably, the location information of the mobile station is anidentifier of the target BSC.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other objects, features and advantages of thepresent invention will become more apparent from the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

[0026]FIG. 1 is a diagram illustrating the state transitions in a mobilecommunication system according to an embodiment of the presentinvention;

[0027]FIG. 2 is a diagram illustrating a structure of a network having aseparate entralized database according to an embodiment of the presentinvention;

[0028]FIG. 3A is a diagram illustrating a structure of a network inwhich the entralized database is unified in a VLR according to anembodiment of the resent invention;

[0029]FIG. 3B is a diagram illustrating a structure of a network havingthe entralized database as an internal module of a specific BSCaccording to an embodiment of the present invention;

[0030]FIG. 4 is a diagram illustrating a structure of the centralizeddatabase according to an embodiment of the present invention;

[0031]FIG. 5 is a diagram illustrating configuration of dormantinformation stored in a dormant state database according to anembodiment of the present invention;

[0032]FIG. 6 is a diagram illustrating a structure of a centralizeddatabase agent module according to an embodiment of the presentinvention;

[0033]FIG. 7 is a diagram illustrating configuration of informationstored in a database of a source BSC according to an embodiment of thepresent invention;

[0034]FIG. 8 is a diagram illustrating a procedure for exchangingmessages during initial packet call setup in the case where the sourceBSC is fixed, according to an embodiment of the present invention;

[0035]FIG. 9 is a diagram illustrating a procedure for exchangingmessages to update mobility management information of a packet terminalin the case where he source BSC is fixed, according to an embodiment ofthe present invention;

[0036]FIG. 10 is a diagram illustrating a procedure for exchangingmessages due to an origination call from the packet terminal in the casewhere the source BSC is fixed, according to an embodiment of the presentinvention;

[0037]FIG. 11 is a diagram illustrating a procedure for exchangingmessages due to a termination call to the packet terminal in the casewhere the source BSC is fixed, according to an embodiment of the presentinvention;

[0038]FIG. 12 is a diagram illustrating a procedure for exchangingmessages during initial packet call setup in the case where the sourceBSC is dynamic, according to another embodiment of the presentinvention;

[0039]FIG. 13 is a diagram illustrating a procedure for exchangingmessages to update mobility management information of a packet terminalin the case where the source BSC is dynamic, according to anotherembodiment of the present invention;

[0040]FIG. 14 is a diagram illustrating a procedure for exchangingmessages due to an origination call from the packet terminal in the casewhere the source BSC is dynamic, according to another embodiment of thepresent invention; and

[0041]FIG. 15 is a diagram illustrating a procedure for exchangingmessages due to a termination call to the packet terminal in the casewhere the source BSC is dynamic, according to another embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0042] A preferred embodiment of the present invention will be describedherein below with reference to the accompanying drawings. In thefollowing description, well-known functions or constructions are notdescribed in detail since they would obscure the invention inunnecessary detail. In addition, the present invention can be applied toany wireless packet data system supporting the high-speed packet dataservice having the “packet activation” and “packet deactivation”attributes such as an IS-95B system, as well as the future mobilecommunication system such as the CDMA-200 system and the W-CDMA system.

[0043] Herein, the invention will be described with reference to aCDMA-2000 system operating under the TIA (Telecommunication IndustryAssociation) standard, and the “mobile communication system” refers to aCDMA system.

[0044] A channel structure of the CDMA-2000 system to which the presentinvention is applied is divided into logical channels and physicalchannels. In this case, the major logical channels and the majorphysical channels used by a MAC (Medium Access Control) channel of theCDMA-2000 system are defined as follows. For convenience, a prefix “r-”will be attached to reverse channels, while a prefix “f-” will beattached to forward channels.

[0045] First, a function of the logical channels will be described indetail.

[0046] A dedicated signaling channel (dsch) is exclusively assigned to aspecific mobile only in the active state or the control hold state. Inaddition, the dsch is used for transmitting and receiving anL3/Call-Control control message.

[0047] A dedicated MAC channel (dmch) is also exclusively assigned to aspecific mobile only in the active state or the control hold state. Inaddition, the dmch is used for transmitting and receiving a controlmessage of a MAC layer to control a dedicated traffic channel (dtch),and chiefly manages 5 ms-messages.

[0048] A common MAC channel (cmch) is commonly assigned to a pluralityof mobiles only in the suspended state or the dormant state. Inaddition, the cmch is used for transmitting and receiving a controlmessage of the MAC layer.

[0049] A dedicated traffic channel (dtch) is exclusively assigned to aspecific mobile only in the active state, and used for transmitting andreceiving the traffic.

[0050] A common traffic channel (ctch) is commonly assigned to aplurality of mobiles only in the dormant state, and used fortransmitting and receiving the traffic.

[0051] Next, a function of the physical channels will be described indetail.

[0052] A dedicated control channel (DCCH) is exclusively assigned to aspecific mobile to control the mobile. In addition, the DCCH supports aDTX (Discontinuous Transmission) mode where the channel band is usedonly when there exists the traffic to transmit. The respective usersshare one code by using different orthogonal long codes.

[0053] A common control channel (CCCH) is acquired by a plurality ofmobiles through competition, and is mapped with the logical channelcmch.

[0054] A fundamental channel (FCH) is a channel provided consideringreverse compatibility with the IS-95 system, and can be utilized fortransmitting and receiving traffic control information like theconventional IS-95 fundamental channel.

[0055] A supplemental channel (SCH) is a channel corresponding to theIS-95B supplemental channel, and is based on an outband technique forchiefly transmitting the traffic. The SCH supports a scheme which isdynamically assigned or released by the logical dmch.

[0056]FIG. 1 illustrates state transitions of a MAC layer in a mobilecommunication system according to an embodiment of the presentinvention. Referring to FIG. 1, the MAC layer has a different stateaccording to a channel holding state, and each state transition takesplace through a timer or an artificial primitive. The respective statesshown in FIG. 1 will be described below.

[0057] A null state 110 is a pre-call setup state where there is noconnection and no information. An initialization state 112 is a statewhere negotiations are carried out at an initialization request of apacket service, and in this state, call processing and variousnegotiations are performed through a common channel. A control holdstate 114 is a state where the dedicated control channels dsch/dmch areestablished after the channel negotiation. In this case, the trafficchannel is immediately assigned through the dmch. An active state 116 isa state where due to activation of the traffic, the dedicated trafficchannel dtch is assigned through the dmch, and then, the traffic istransmitted and received through the assigned channel. A suspended state118 is a state where the dedicated channels dsch/dmch are released andvarious control information is transmitted and received through thecommon channel. A dormant state 110 is a state where due to no trafficis exchanged for a long time, every channel under the layer 2 isreleased and all the information is removed. In this state, only thePPP-related access information is managed. Finally, a reconnect state122 is a state to which transition occurs if transmission traffic isgenerated in the dormant state 120, and in this state, the sameprocedure as the initial call setup procedure is performed except thefact that the PPP information is maintained.

[0058] Meanwhile, the state transitions take place based on a timer, asshown in FIG. 1. That is, transition to the control hold state 114happens only when no traffic is exchanged for a set time T_active aftertransition to the active state 116 by acquiring the dedicated trafficchannel in the control hold state 114. When no traffic is exchanged fora set time T_hold in the control hold state 114, transition occurs tothe suspended state 118. If the non-traffic state (the state that notraffic is exchanged) is maintained until expiration of a set timeT_suspend in the suspended state 118, transition to the dormant state110 takes place. Although the state transition diagram of FIG. 1includes the suspended state 118, an embodiment of the invention canalso be applied to a system excluding the suspended state. In this case,if no traffic is generated for the set time T_active in the active state116, transition will happen directly to the dormant state 120 throughthe control hold state 114.

[0059] The invention manages a call of the mobile in the dormant stateamong the above states of the MAC layer, so as to rapidly transition tothe active state when it is necessary to resume transmitting the packetdata of the mobile. To this end, a structure of a centralized database(hereinafter, referred to as a “centralized DB”) and dormant informationmanaged by the centralized DB must be defined. In addition, a structureof a source BSC providing a packet service for the mobile in the dormantstate and a database managed by the source BSC must be also defined.

[0060] Structure of Centralized DB

[0061] As mentioned above, the present invention embodies thecentralized DB for managing the dormant information of the mobiles. Itis possible to consider the following two plans in embodying thecentralized DB.

[0062] A first plan is to construct the centralized DB with a separatesoftware or device. In this case, the corresponding network has astructure shown in FIG. 2. As illustrated in FIG. 2, the centralized DB,as a separate software or device, is connected to a global accessnetwork (GAN) which connects the network elements to one another. TheGAN shown in FIG. 2 is represented by a packet data switch for switchingamong a plurality of BSCs, the centralized DB and a packet data switchnode (PDP (Packet Data Processor)).

[0063] In a second plan, in the existing mobile communication systemchiefly supporting the voice call, a mobile merges the centralized DBinto the VLR managing the location information, or develops or connectsthe centralized DB to an internal module in a specific BSC. In thiscase, the corresponding network has the structures shown in FIGS. 3A and3B.

[0064] Although the physical location of the centralized DB is differentin the above two plans, the centralized DB has the same operation.Therefore, the structure and operation of the embodiment will bedescribed with reference to the first plan shown in FIG. 2.

[0065] The centralized DB must be so embodied to manage the dormantinformation of the mobiles. Preferably, the centralized DB proposed asan example of the present invention has a structure shown in FIG. 4.

[0066] Referring to FIG. 4, a centralized DB 400 according to anembodiment of the present invention includes an interface processor 402,a transaction processor 404 and a dormant state database 406. Theinterface processor 402 provides a communication-related input/outputinterface for exchanging information with the BSCs or MSC/VLR by thecentralized DB 400. The transaction processor 404 supports a functionof, upon receipt of a query message from the BSC and MSC/VLR, searchingthe dormant state database 406 for the corresponding information andthen transmitting a response. In addition, the transaction processor 404supports a function of updating the information managed by the dormantstate database 406 based on the information from the BSCs and MSC/VLR.The dormant state database 406 is an information storage for storinginformation on the mobiles (or mobile stations (MSs)) existing in thedormant state.

[0067] Configuration of Dormant Information

[0068] Meanwhile, the dormant state database 406 included in thecentralized DB 400 must store the MS information (hereinafter, referredto as “dormant information”) required to implement the invention. Thedormant information stored in the dormant state database 406 has theconfiguration shown in FIG. 5. The information shown in FIG. 5 can beclassified into mandatory information and optional information. Themandatory information is information required for a service of the MSwhich has entered the dormant state, while the optional information isinformation required for efficiently supporting the packet service ofthe MS by a wire network. Herein, the optional information is,information necessary for supporting rapid reconnection by omitting theadditional negotiation and authentication process when the MS in thedormant state transits to the active state.

[0069] First, as to the mandatory information shown in FIG. 5, IMSI(International Mobile Station Identifier) indicates an identifier foridentifying the MS, and Location Information indicates information onthe place where the MS having entered the dormant state is currentlylocated. Further, Last Registration Time indicates the last time whenthe MS has performed communication, and Source BSC ID indicates anidentifier of a BSC where a source packet data processor (PDP) of the MSexists. The PDP is a processor for managing a communication interfacebetween a PDSN (Packet Data Switch Node) and a BSC. The PDSN is anexternal packet network, and the Internet is a typical example of it.

[0070] Through the mandatory information, the invention identifies theMS transited from the dormant state to the active state depending on theIMSI and then detects the source BSC where there exists the connectionto the PDSN, used by the corresponding MS in the active state. Besides,when it is not necessary to manage the dormant information any longerbecause the MS has moved to another MSC area, the dormant informationassociated with the corresponding MS is deleted after a lapse of apredetermined time starting from the last registration time. Further,the invention traces the location of the MS in the dormant state for thetraffic received from the PDSN.

[0071] Next, as to the optional information shown in FIG. 5, ServiceReference indicates an identifier for the connections used by the MSwhile performing the packet data service, and TMSI (Temporary MobileStation Identifier) indicates an identifier temporarily assigned to theMS from the network. -Subscriber Profile means information on the MS ora subscriber using the radio packet service, Service Option meanscapability information indicating whether it is possible to support suchservices as voice, packet and facsimile services, and ServiceConfiguration means the configuration of information on channelstructure, data rate and quality of the service supported.

[0072] Structure of Source BSC

[0073] A structure of a centralized DB agent module of a source BSCaccording to an embodiment of the present invention is illustrated inFIG. 6. As illustrated, the centralized DB agent module according to anembodiment of the present invention includes a mobility managementmodule 610, a call control module 612, a radio resource managementmodule 614, and an interface module 620.

[0074] The mobility management module 610 performs a process related tothe mobility of the MS, the call control module 612 performs callsetup/release and call management for the voice or packet service of theMS, and the radio resource management module 614 supports management andassignment/release of the radio resources. The interface module 620, amodule for managing the dormant state of the MS to serve as a sourceBSC, includes an interface processor 622, an agent processor 624, and asource BSC database 626.

[0075] The interface processor 622 is a communication input/outputmodule for enabling various modules in the BSC to communicate with theagent processor 624 performing the connection with the centralized DB400. The agent processor 624 transmits an information search request andan information update request received from the various modules in theBSC to the centralized DB, and then, processes the results. The sourceBSC database 626 stores information necessary for serving as a sourceBSC for the MS.

[0076] Structure of Source BSC Database

[0077] Meanwhile, the source BSC database managed by the source BSC tosupport the dormant state of the MS has a structure shown in FIG. 7.Referring to FIG. 7, IMSI (International Mobile Station Identifier)indicates an identifier for identifying the MS, and ATM Connection IDindicates an identifier for identifying ATM (Asynchronous Transfer Mode)connection established between the source BSC and the PDSN while the MSperforms the packet service. Out-Of-Data Flag is a flag for indicatingthat the corresponding information will be deleted after a lapse ofpredetermined time, if the MS having entered the dormant state fails toenter the active state for a long time.

[0078] Among the above fields, the ATM Connection ID field indicates achannel identifier used when the source BSC is connected to the PDSN inthe ATM mode. Otherwise, when the source BSC is connected to the PDSN inanother communication mode, a different channel identifier for thecorresponding communication mode is used.

[0079] Besides, like the centralized DB, the source BSC database has theoptional information required for enabling the wire network toeffectively support a packet service of the MS. Here, the optionalinformation is information necessary for supporting rapid reconnectionby omitting the additional negotiation and authentication process whenthe MS in the dormant state transits to the active state. Referring toFIG. 7, Subscriber Profile means information on the MS or a subscriberusing the radio packet service, Service Option means capabilityinformation indicating whether it is possible to support such servicesas voice, packet and facsimile services, and Service Configuration meansthe configuration of information on channel structure, data rate andquality of the service supported.

[0080] Meanwhile, the present invention proposes following twoapproaches based on the above structures, in order to effectively managethe MSs in the dormant state.

[0081] A first approach is a “fixed source BSC plan”, in which once theMS initiates the call, the source BSC continuously serves as a sourceuntil the corresponding MS releases the packet service. Such an approachis relatively easy to embody. That is, since the traffic and the signalpath are simply extended according to movement of the MS, this approachcan be simply embodied. Therefore, it is possible to effectively supportthe packet service of the MS in the initial stage of the packet service.Message exchange scenarios required for embodying the first proposedplan are illustrated in FIGS. 8 to 11.

[0082] A second approach is a “dynamic source BSC plan”, unlike thefirst approach where the source BSC is not changed until the packetservice of the MS is released. The dynamic source BSC plan is to movethe source BSC for the MS to the BSC of a cell to which the MS belongs,as the MS moves. That is, the second approach is proposed to resolve theproblem that occurs when a traffic path passes through a plurality ofBSCs, as the MS moves. Message exchange scenarios required for embodyingthe second proposed plan are illustrated in FIGS. 12 to 14.

[0083] Now, a detailed description of the two proposed plans will bemade with reference to the above structures. There have been proposedthree different plan-based networks for the centralized DB according toan embodiment of the present invention. Herein, however, the descriptionof the invention will be made with reference to the network based on theplan in which the centralized DB is constructed as a separate module, asset forth in FIG. 2. This is because the operation is performed in asimilar manner although the invention is applied to any of the threeproposed plans.

[0084] A message processing operation based on the “fixed source BSCplan” according to an embodiment of the present invention will bedescribed with reference to the message exchange scenarios shown inFIGS. 8 to 11.

[0085] First, a message exchange scenario performed during initialpacket call setup in the case where the source BSC is fixed will bedescribed with reference to FIG. 8. Referring to FIG. 8, in Step #1, theMS transmits an origination message to the BSC to attempt a PPP(Point-to-Point Protocol) access for the purpose of a packet service.Here, the BSC becomes a source BSC. The transmitted origination messageis received at the BSC serving a cell in which the MS is located. InStep #2, upon receipt of the origination message, the BSC transmits tothe centralized DB 400 a query message Serv_Query_MSG followed by anacknowledgement from the MS. The query message Serv_Query_MSG includesIMSI information designating the MS that has transmitted the originationmessage.

[0086] The centralized DB 400 processes the Serv_Query_MSG transmittedfrom the BSC. More specifically, the interface processor 402 in thecentralized DB 400 receives the Serv_Query_MSG, and provides it to thetransaction processor 404. The transaction processor 404 then searchesthe dormant information stored in the dormant state DB 406, anddetermines whether there exists the dormant information corresponding tothe Serv_Query_MSG. Determining whether there exists the dormantinformation is performed by determining whether there exists dormantinformation corresponding to the IMSI included in the Serv_Query_MSG.The dormant information, as described with reference to FIG. 5, isinformation required for the rapid reconnection or for tracking thelocation of the dormant state MS.

[0087] If the Serv_Query_MSG provided by the origination message fromthe MS is for the transition from the dormant state to the active state,the corresponding dormant information is stored in the dormant state DB406. If the MS requests the packet service for the first time, or thatthe MS request the packet service for the first time after moving fromanother MSC the corresponding dormant information is not stored in thedormant state DB 406. If it is determined through the search that thedormant information of the corresponding MS is not stored, thetransaction processor 404 transmits to the BSC a response messageServ_Result_MSG indicating that there is no dormant information for theMS, in Step #3. However, if it is determined that the dormantinformation of the corresponding MS is stored, an operation of FIG. 10is performed, which will be described later.

[0088] Upon receipt of the Serv_Result_MSG from the centralized DB 400,the BSC determines whether the origination message received from the MSis an origination message caused by a new call or a call incoming fromanother MSC. Determining whether to designate the BSC as a source BSCfor the corresponding MS is performed based on whether the originationmessage is an origination message caused by a new call or a callincoming from another MSC. If it is determined from the Serv_Result_MSGthat the origination message from the MS is an origination messagecaused by a new call or a call incoming from another MSC, the BSCassigns an internal traffic processor (ATP) according to a loadbalancing rule. The ATP is a processor for controlling the overalloperation for providing the packet service to the MS. In addition to theassignment of the ATP, the source BSC sets as a new call the informationcaused by the call attempted by the MS through the MSC/VLR, and thenseparately manages information on the set new call. In order toconfigure the information on the new call, it is necessary to determinePPP address and PPP ID of the PDP (PDSN).

[0089] The operation of registering a new call through the MSC/VLR is anoperation commonly performed to provide an initial packet service, sothe detailed description will be omitted. When the new call setupprocess is completed, the MS performs the packet communication servicethrough the source BSC according to the standard.

[0090] During the packet communication service, the source BSC monitorswhether the MS transits to the suspended state or the dormant state. Asmentioned above, the transition to the suspended state or the dormantstate takes place when no data is exchanged for a predetermined time.Upon detecting the MS's transition to the suspended state or the dormantstate, the source BSC proceeds to Step #4-1. In Step #4-1, the sourceBSC releases the currently assigned connection (channel) by transmittinga release message to the MS. Further, in Step #4-2, the source BSCtransmits to the centralized DB 400 a Serv_Update_MSG message forrequesting update of the dormant information corresponding to the MStransited to the suspended state or the dormant state. Here, theServ_Update_MSG includes the dormant information of the correspondingMS. The dormant information is information necessary for the resumptionof the packet service to the MS transited to the suspended state or thedormant state, and its exemplary structure is shown in FIG. 5.

[0091] Upon receipt of the Serv_Update_MSG, the centralized DB 400creates a new DB field into its internal dormant state DB 406, andstores the dormant information included in the Serv_Update_MSG in thecreated field. After completion of storing the dormant information, thecentralized DB 400 proceeds to Step #4-3 to transmit to the source BSC aServ_Update_Ack_MSG message indicating that update of the dormantinformation has been normally completed, thus completing the initialpacket call setup process.

[0092] Although a detailed description has not been made regarding acommon operation in which the state transition does not happen and thepacket service is normally ended after the MS sets up the initial packetcall, the operation will be performed in the same process as theconventional process.

[0093] The above embodiment has disclosed a scheme for updating thedormant information of the MS in the centralized DB 400 at the point intime where the MS transits from the active state to the suspended stateor the dormant state after completion of the initial packet call setup.However, an alternative embodiment creates a new DB field prior toperforming the packet service when there exists no information on thecorresponding call in the centralized DB 400, and then updates thedormant information of the MS for the call. In this case, it isnecessary to define a field for the dormant information to be updated inthe Serv_Query_MSG transmitted in Step #2 of FIG. 8, and the procedureperformed in Steps #4-2 and #4-3 of FIG. 8 must be included in theprocedure performed in Steps #2 and #3 of FIG. 8.

[0094] Second, in a message exchange scenario for update of the mobilitymanagement information of a packet terminal in the case where the sourceBSC is fixed, a target BSC updates location information of the dormantinformation of managed in the centralized DB upon receipt of aregistration message due to an idle handoff of the dormant state MS.This will be described in detail with reference to FIG. 9.

[0095] Referring to FIG. 9, in Step #1, the MS in the dormant statetransmits a registration message due to an idle handoff, and thelocation registration message transmitted by the MS is received at atarget BSC. The “target BSC” refers to a BSC to which the moving MSdesires to be registered. Upon receipt of the location registrationmessage in Step #1, the target BSC transmits, though not illustrated, alocation updating request message to the MSC to update the locationinformation managed in the VLR.

[0096] In Step #2, the target BSC transmits a location update msgLoc_Query_Update_MSG to the centralized DB 400 to determine whether apacket service of the MS from which the registration message has beenreceived is activated and updates the location information. TheLoc_Query_Update_MSG must include the IMSI for identifying thecorresponding MS. The location information, as stated above, isinformation on the place where the MS is currently located. For example,a BSC identifier for identifying the target BSC can be used for thelocation information. Upon receipt of the Loc_Query_Update_MSG, thecentralized DB 400 determines whether there exists the dormantinformation for the corresponding MS using the IMSI constituting theLoc_Query_Update_MSG. If it is determined that the dormant informationof the MS exists, the centralized DB 400 determines that thecorresponding MS is a dormant state MS whose packet service isactivated, using a location update result message Loc_Result_MSGtransmitted to the target BSC in Step #3. In addition, the centralizedDB 400 updates the location information for the MS based on the locationinformation (identifier of the target BSC) constituting theLoc_Query_Update_MSG. Upon receipt of the location result messageLoc_Result_MSG indicating activation of the packet service, the targetBSC regards the packet service state of the corresponding MS as thedormant state or the null state. The reason is because the dormantinformation managed in the centralized DB 400 proves that thecorresponding MS is in the dormant state or the null state. However,upon failure to find the dormant information for the corresponding MS,the centralized DB 400 informs that the packet service of the MS is notactivated, using the location result message Loc_Result_MSG transmittedto the target BSC in Step #3.

[0097] Third, in a message exchange scenario caused by an originationcall from a packet terminal in the case where the source BSC is fixed, atarget BSC is provided with the dormant information for thecorresponding MS from the centralized DB 400 upon receipt of anorigination message from the MS in the dormant state, and provides apacket service to the corresponding MS using the provided dormantinformation. This will be described in detail with reference to FIG. 10.

[0098] In order to resume the packet service, the MS in the dormantstate transmits an origination message to the BSC. That the MS in thedormant state has transmitted an origination message is equivalent torequesting transition to the active state. Referring to FIG. 10, in Step#1, the transmitted origination message is provided to a BSC where theMS is currently located. Here, the BSC provided with the originationmessage becomes a target BSC of the MS. In Step #2, the target BSCtransmits to the centralized DB 400 a dormant information requestmessage Serv_Query_MSG for requesting dormant information of the MS. TheServ_Query_MSG must include IMSI for selecting dormant information forthe MS out of the information stored in the centralized DB 400 and atarget BSC ID for providing the selected dormant information.

[0099] Upon receipt of the Serv_Query_MSG, the centralized DB 400searches the dormant information of the corresponding MS based on theIMSI included in the Serv_Query_MSG. Searching the dormant informationis performed by comparing the IMSIs stored in the centralized DB 400with the IMSI provided from the target BSC and determining whether thereexists the same IMSI. After completing the dormant search, thecentralized DB 400 transmits the search results to the target BSCthrough a search result message Serv_Result_MSG in Step #3 of FIG. 10.The Serv_Result_MSG has dormant information including the source BSC ID.Upon receipt of the dormant information of the corresponding MS throughthe Serv_Result_MSG, the target BSC attempts packet call connection tothe source BSC in Step #4. If the packet call connection is set up, thepacket call to the MS is reconnected by connecting the internal PDP tothe network through the source BSC. This means the transition from thedormant state to the active state.

[0100] Therefore, by managing the dormant information for the MS in thedormant state in the centralized DB 400 accessible by every BSC in thesame MSC, it is possible to rapidly perform the packet service when thetransition to the active state occurs due to the call origination by theMS.

[0101] Fourth, in a message exchange scenario caused by a terminationcall to a packet terminal in the case where the source BSC is fixed, ifa termination call to the dormant state MS located in a target BSC isgenerated from the MSC, a source BSC informs the target BSC of theterminal call by consulting the centralized DB 400, and the target BSCprovides the information to the corresponding MS, thus provides a packetservice to the MS by receiving a response message. This will bedescribed in detail with reference to FIG. 11.

[0102] Referring to FIG. 11, in Step #1, the source BSC receives apacket arrival ,event upon receipt of a termination call requestingtermination to a certain MS from a given PDP through an interface link(a communication link between the source BSC and the PDSN). In Step #2,the source BSC transmits to the centralized DB 400 a query messageLoc_Query_MSG (MISI) for determining a location of the corresponding MSin response to the termination call. The query message Loc_Query_MSGincludes IMSI information for identifying the MS. The centralized DB 400searches the location information of the corresponding MS based on theIMSI. After the search, the centralized DB 400 transmits the searchedlocation information of the MS to the source BSC through a locationinformation message Loc_Result_MSG (Loc Info) in Step #3. Upon receiptof the location information of the MS, the source BSC analyzes thelocation of the corresponding MS based on the received locationinformation. After analyzing the location of the MS, the source BSCtransmits a paging request message to the target BSC where the MS islocated, in Step #4. Though not illustrated in the drawing, upon failureto receive a response message Paging_Response_Ack_MSG in response to thepaging request message for a predetermined time, the source BSC performsan operation according to a paging algorithm.

[0103] Upon receipt of the paging request message, the target BSCtransmits a page message Page_MSG to every MS in its cell area through abroadcasting channel in Step #5. Upon receipt of the page messagetransmitted through the broadcasting channel, the MS transmits a pageresponse message to the target BSC in response to the page message inStep #6. Upon receipt of the page response message, the target BSCtransmits a paging response acknowledge message to the source BSC inorder to set up a packet call in Step #7. Upon receipt of the pagingresponse acknowledge message from the target BSC, the source BSCtransmits a packet call connection message for call connection to thetarget BSC in Step #8. Upon receipt of the packet call connectionmessage, the target BSC performs an operation for the packet service.

[0104] A packet reception path to the MS for the packet service isconnected in the sequence of PDP (PDSN)→source BSC→target BSC→MS asrepresented by a bold solid line. On the other hand, a transmission pathfrom the MS for the packet service has a reverse direction of thereception path.

[0105] To sum up, in the first plan, if the MS initially sets up a callat BSC#l and then moves to BSC#2, BSC#3 and BSC#4, a traffic path forthe packet service caused by a termination call is set in the sequenceof PDSN→source BSC#1→BSC#2→BSC#3→BSC#4→MS, while a traffic path for thepacket service caused by an origination call is set in the sequence ofMS→BSC#4→BSC#3→BSC#2→source BSC#1→PDSN.

[0106] Next, a message processing operation based on the “dynamic sourceBSC plan” according to another embodiment of the present invention willbe described with reference to the message exchange scenarios shown inFIGS. 12 to 15.

[0107] First, a message exchange scenario performed during initial,packet call setup in the case where the source BSC is dynamicallychanged according to movement of the MS will be described with referenceto FIG. 12. Referring to FIG. 12, in Step #1, the MS transmits anorigination message to the BSC to attempt a PPP (Point-to-PointProtocol) access for the purpose of a packet service. The transmittedorigination message is received at the BSC serving a cell to which theMS belongs. In Step #2, upon receipt of the origination message, the BSCtransmits to the centralized DB 400 a query message Serv_Query_MSGfollowed by an acknowledgement from the MS. The query messageServ_Query_MSG includes information (MS identifier, hereinafter referredto as IMSI) designating the MS that has transmitted the originationmessage.

[0108] The centralized DB 400 processes the Serv_Query_MSG transmittedfrom the BSC. More specifically, the interface processor 402 in thecentralized DB 400 receives the Serv_Query_MSG, and provides it to thetransaction processor 404. The transaction processor 404 then searchesthe dormant information stored in the dormant state DB 406, anddetermines whether there exists the dormant information corresponding tothe Serv_Query_MSG. Determining whether there exists the dormantinformation is performed by determining whether there exists dormantinformation corresponding to the IMSI included in the Serv_Query_MSG.The dormant information, as described with reference to FIG. 5, isinformation required for the rapid reconnection or for tracking thelocation of the dormant state MS.

[0109] If the Serv_Query_MSG provided by the origination message fromthe MS is for the transition from the dormant state to the active state,the corresponding dormant information is stored in the dormant state DB406. If the MS requests the packet service for the first time, or thatthe MS request the packet service for the first time after moving fromanother MSC, the corresponding dormant information is not stored in thedormant state DB 406. If it is determined through the search that thedormant information of the corresponding MS is not stored, thetransaction processor 404 transmits to the BSC a response messageServ_Result_MSG indicating that there is no dormant information for theMS, in Step #3. However, if it is determined that the dormantinformation of the corresponding MS is stored, an operation of FIG. 110is performed, which will be described later.

[0110] Upon receipt of the Serv_Result_MSG from the centralized DB 400,the BSC determines whether the origination message received from the MSis an origination message caused by a new call or a call incoming fromanother MSC. Determining whether to designate the BSC as a source BSCfor the corresponding MS is performed based on whether the originationmessage is an origination message caused by a new call or a callincoming from another MSC. If it is determined from the Serv_Result_MSGthat the origination message from the MS is an origination messagecaused by a new call or a call incoming from another MSC, the BSCassigns an internal traffic processor (ATP) according to a loadbalancing rule. The ATP is a processor for controlling the overalloperation for providing the packet service to the MS. In addition toassignment of the ATP, the source BSC sets as a new call the informationcaused by the call attempted by the MS through the MSC/VLR, and thenseparately manages information on the set new call. In order toconfigure the information on the new call, it is necessary to determinePPP address and PPP ID of the PDP (PDSN).

[0111] The operation of registering a new call through the MSC-VLR is anoperation commonly performed to provide an initial packet service, sothe detailed description will be omitted. When the new call setupprocess is completed, the MS performs the packet communication servicethrough the source BSC according to the standard.

[0112] During the packet communication service, the source BSC monitorswhether the MS transits to the suspended state or the dormant state. Asmentioned above, the transition to the suspended state or the dormantstate takes place when no data is exchanged for a predetermined time.Upon detecting the MS's transition to the suspended state or the dormantstate, the source BSC proceeds to Step #4-1. In Step #4-1, the sourceBSC releases the currently assigned connection (channel) by transmittinga release message to the MS. Further, in Step #4-2, the source BSCtransmits to the centralized DB 400 a Serv_Update_MSG message forrequesting update of the dormant information corresponding to the MStransited to the suspended state or the dormant state. Here, theServ_Update_MSG must include the dormant information of thecorresponding MS. The dormant information means information necessaryfor resumption of the packet service to the MS transited to thesuspended state or the dormant state, and its exemplary structure isshown in FIG. 5.

[0113] Upon receipt of the Serv_Update_MSG, the centralized DB 400creates a new DB field into its internal dormant state DB 406, andstores the dormant information included in the Serv_Update_MSG in thecreated field. After completion of storing the dormant information, thecentralized DB 400 proceeds to Step #4-3 to transmit to the source BSC aServ_Update_Ack_MSG message indicating that update of the dormantinformation has been normally completed, thus completing the initialpacket call setup process.

[0114] Although a detailed description has not been made regarding acommon operation in which the state transition does not happen and thepacket service is normally ended after the MS sets up the initial packetcall, the operation will be performed in the same process as theconventional process.

[0115] The above embodiment has disclosed a scheme for updating thedormant information of the MS in the centralized DB 400 at the point intime where the MS transits from the active state to the suspended stateor the dormant state after completion of the initial packet call setup.However, an alternative embodiment creates a new DB field prior toperforming the packet service when there exists no information on thecorresponding call in the centralized DB 400, and then updates thedormant information of the MS for the call. In this case, it isnecessary to define a field for recording the dormant information to beupdated in the Serv_Query_MSG transmitted in Step #2 of FIG. 12, and theprocedure performed in Steps #4-2 and #4-3 of FIG. 12 must be includedin the procedure performed in Steps #2 and #3 of FIG. 12.

[0116] Second, a message exchange scenario for update of the mobilitymanagement information of a packet terminal in the case where the sourceBSC is dynamically changed according to movement of the MS, will bedescribed in detail with reference to FIG. 13.

[0117] Referring to FIG. 13, in Step #1, the MS in the dormant statetransmits a registration message due to an idle handoff, and thelocation registration message transmitted by the MS is received at atarget BSC. The “target BSC” refers to a BSC to which the moving MSdesires to be registered. That is, the target BSC includes all the BSCsother than the source BSC of the corresponding MS, among the BSCsconstituting the same MSC. Upon receipt of the location registrationmessage in Step #1, the target BSC transmits, though not illustrated, alocation updating request message to the MSC to update the locationinformation managed in the VLR.

[0118] In Step #2, the target BSC transmits a location update messageLoc_Query_Update_MSG to centralized DB 400 to determine whether a packetservice of the MS from which the registration message has been receivedis activated and updates the location information. TheLoc_Query_Update_MSG must include the IMSI for identifying thecorresponding MS. The location information, as stated above, isinformation on the place where the MS is currently located. For example,a BSC identifier for identifying the target BSC can be used for thelocation information. Upon receipt of the Loc_Query_Update_MSG, thecentralized DB 400 transmits in Step #3 to a PDP a location informationupdate request message Loc_Update_Source_MSG for requesting that thesource BSC corresponding to the MS that has transmitted the registrationmessage should be changed to a target BSC. Upon receipt of the locationinformation update request message Loc_Update_Source_MSG, the PDPtransmits an acknowledge message Loc_Update_Ack_MSG to the centralizedDB 400 after designating the target BSC as a new source BSC.

[0119] Upon receipt of the acknowledge message Loc_Update_Ack_MSG, thecentralized DB 400 searches for the MS in the dormant information usingthe IMSI in the Loc_Query_Update_MSG. After finding the dormantinformation for the MS, the centralized DB 400 informs that thecorresponding MS is a dormant state MS whose packet service isactivated, using a location result message Loc_Result_MSG transmitted tothe updated source BSC in Step #5. In addition, the centralized DB 400updates the location information for the MS based on the locationinformation (identifier of the target BSC) constituting theLoc_Query_Update_MSG. Upon receipt of the location result messageLoc_Result_MSG indicating activation of the packet service, the updatedsource BSC regards the packet service state of the corresponding MS asthe dormant state or the null state. The fact that the dormantinformation is managed in the centralized DB 400 proves that thecorresponding MS is in the dormant state or the null state. However,upon failure to find the dormant information for the corresponding MS,the centralized DB 400 informs that the packet service of the MS is notactivated, using the location result message Loc_Result_MSG transmittedto the updated source BSC in Step #5.

[0120] Third, a message exchange scenario caused by an origination callfrom a packet terminal in the case of the source BSC is dynamicallychanged according to movement of the MS will be described in detail withreference to FIG. 14.

[0121] In order to resume the packet service, the MS in the dormantstate transmits an origination message to the BSC. The fact that the MSin the dormant state has transmitted an origination message isequivalent to requesting transition to the active state. Referring toFIG. 14, in Step #1, the transmitted origination message is provided toa BSC where the MS is currently located. Here, the BSC provided with theorigination message becomes a target BSC of the MS. In Step #2, thetarget BSC transmits to the centralized DB 400 a dormant informationrequest message Serv_Query_MSG for requesting dormant information of theMS. The Serv_Query_MSG must include the IMSI for selecting dormantinformation for the MS out of the information stored in the centralizedDB 400 and a target BSC ID for providing the selected dormantinformation.

[0122] Upon receipt of the Serv_Query_MSG, the centralized DB 400searches the dormant information of the corresponding MS based on theIMSI included in the Serv_Query_MSG. Searching the dormant informationis performed by comparing the IMSIs stored in the centralized DB 400with the IMSI provided from the target BSC and determining whether thereexists the same IMSI. After completing the dormant search, thecentralized DB 400 transmits the search results to the target BSCthrough a search result message Serv_Result_MSG in Step #3 of FIG. 14.The Serv_Result_MSG has dormant information including the source BSC ID.Upon receipt of the dormant information of the corresponding MS throughthe Serv_Result_MSG, the target BSC connects a packet call to the MS byconnecting the internal PDP to the network based on the provided dormantinformation in Step #4 of FIG. 14.

[0123] Therefore, by managing the dormant information for the MS in thedormant state in the centralized DB 400 accessible by every BSC in thesame MSC, it is possible to rapidly perform the packet service when thetransition to the active state occurs due to the call origination by theMS.

[0124] As described above, when the source BSC is dynamically changedaccording to movement of the MS, the target BSC is designated as a newsource BSC in the centralized DB 400, so that the packet service isperformed without passing through the existing source BSC. That is, thetarget BSC (the updated source BSC) performs the packet service directlywith the PDP (PDSN).

[0125] Fourth, a message exchange scenario caused by a termination callto a packet terminal in the case where the source BSC is dynamicallychanged according to movement of the MS will be described in detail withreference to FIG. 15.

[0126] Referring to FIG. 15, in Step #1, the PDSN transmits a setupmessage to a target BSC upon receipt of a data packet from a certainPDP. In Step #2, the target BSC transmits to the centralized DB 400 aquery message Loc_Query_MSG for determining a location of thecorresponding MS in response to the setup message. The query messageLoc_Query_MSG includes IMSI information for identifying the MS. Thecentralized DB 400 searches the location information of thecorresponding MS based on the IMSI. After completion of the search, thecentralized DB 400 transmits the searched location information of the MSto the target BSC through a message Loc_Result_MSG in Step #3. Uponreceipt of the location information of the MS, the target BSC analyzesthe location of the corresponding MS based on the received locationinformation. After analyzing the location of the MS, the target BSCtransmits a paging request message to itself in Step #4. Though notillustrated in the drawing, upon failure to receive a paging requestacknowledge message for a predetermined time, the target BSC performs apaging algorithm.

[0127] Upon receipt of the paging request message, the target BSCtransmits a page message Page_MSG to every MS in its cell area through abroadcasting channel in Step #5. Upon receipt of the page messagetransmitted through the broadcasting channel, the MS transmits a pageresponse message to the target BSC in response to the page message inStep #6. Upon receipt of the page response message, the target BSCtransmits a paging response acknowledge message to itself in order toset up a packet call in Step #7.

[0128] In Step #8, the target BSC transmits to the centralized DB 400 aquery message Serv_Query_MSG for requesting service information of theMS. Then, in Step #9, the centralized DB 400 searches the serviceinformation of the MS and transmits to the target BSC a Serv_Result_MSGmessage indicating the searched service information. The Serv_Result_MSGincludes PPP information for the MS. The target BSC transmits a packetcall connection request to the PDSN based on the received information.

[0129] A packet reception path to the MS for the packet serviceaccording to the second embodiment is connected in the sequence of PDP(PDSN)→target BSC →MS as represented by a bold solid line. On the otherhand, a transmission path from the MS for the packet service has areverse direction of the reception path.

[0130] As described above, since the PPP information of the packetservice calls entered in the dormant state is managed in the centralizedDB, the present invention has the following advantages:

[0131] (1) The IS-95B or CDMA-2000 mobile communication system canmanage the location of a packet call in the dormant state withoutmodification of BSC/HLR/VLR and MS.

[0132] (2) The BSC can perform by itself call terminal and callorigination on a packet terminal in the dormant state.

[0133] (3) The MS in the dormant state can make a reconnection to aprevious PPP access point in case of call origination.

[0134] (4) It is possible to provide a rapid reconnection function whenthe MS in the dormant state is activated for packet transmission.

[0135] (5) It is possible to support simple structure, which can beembodied with the additional module of the existing devices such as VLRand BSC.

[0136] (6) It is possible to minimize a load on the wire and wirelessstages, since the registration and authentication process is notperformed again during reconnection of the packet call in the dormantstate.

[0137] (7) When the centralized DB is embodied with a separate device,the location management processor such as MSC/VLR has reduced load, sothat it is possible to effectively manage the maximum number ofsubscribers in the MSC.

[0138] While the invention has been shown and described with referenceto a certain preferred embodiment thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention as defined by the appended claims.

What is claimed is:
 1. A method for storing dormant state information ofmobile stations in a dormant state where no packet data is exchangedwith an external packet network, in a centralized database connected toa packet data switch, and updating the dormant state information storedin the centralized database in association with the mobile station whenthe mobile station in the dormant state moves to a target BSC (BaseStation Controller) adjacent to a source BSC in a wireless packet datasystem including a packet data switch node (PDSN) for connecting theexternal packet network to the mobile stations through the packet dataswitch and the source BSC connected to the packet data switch, themethod comprising the steps of: receiving from the mobile station at thetarget BSC a location registration message when the mobile station movesto the target BSC adjacent to the source BSC; upon receipt of thelocation registration message, transmitting from the target BSC to thecentralized database a location update message for updating a locationof the mobile station; upon receipt of the location update message,updating by the centralized database the dormant state information forthe mobile station so as to connect the target BSC to the source BSC;and transmitting from the centralized database to the target BSC alocation update result message indicating complete update of the dormantstate information.
 2. The method as claimed in claim 1, wherein thedormant state information includes an identifier of the mobile station,location information of the mobile station, a last registration time ofthe mobile station, and a source BSC ID of the mobile station.
 3. Themethod as claimed in claim 2, wherein the dormant state informationincludes identifiers for connections used to exchange packet data of themobile station in the dormant state, a temporary identifier assigned tothe mobile station, a service option and service configuration.
 4. Themethod as claimed in claim 1, wherein the location update messageincludes an identifier of the mobile station, and location informationof the mobile station.
 5. The method as claimed in claim 4, wherein thelocation information of the mobile station is an identifier of thetarget BSC.
 6. A method for reconnecting an exchange of packet databetween a mobile station and an external packet network by storingdormant state information of mobile stations in a dormant state where nopacket data is exchanged with the external packet network, in acentralized database connected to a packet data switch, and updating thedormant state information stored in the centralized database inassociation with the mobile station when the mobile station in thedormant state moves to a target BSC adjacent to a source BSC in awireless packet data system including a packet data switch node (PDSN)for connecting the external packet network to the mobile stationsthrough the packet data switch and the source BSC connected to thepacket data switch, the method comprising the steps of: receiving fromthe mobile station at the target BSC an origination message forrequesting transmission of packet data; upon receipt of the originationmessage, transmitting from the target BSC to the centralized database adormant state information request message for requesting dormantinformation; upon receipt of the dormant state information requestmessage, searching by the centralized database dormant state informationstored in association with the mobile station and transmitting thesearched dormant state information using a search result message to thetarget BSC; and upon receipt of the search result message, transmittingfrom the target BSC to the source BSC, a packet call connection messagefor requesting reconnection of the packet call and thus connecting thesource BSC to the target BSC through the packet data switch.
 7. Themethod as claimed in claim 6, wherein the dormant state informationincludes an identifier of the mobile station, location information ofthe mobile station, a last registration time of the mobile station, anda source BSC ID of the mobile station.
 8. The method as claimed in claim7, wherein the dormant state information includes identifiers forconnections used to exchange packet data of the mobile station in thedormant state, a temporary identifier assigned to the mobile station, aservice option and service configuration.
 9. The method as claimed inclaim 6, wherein the dormant state information request message includesan identifier of the mobile station, and an identifier of the targetBSC.
 10. The method as claimed in claim 6, wherein the search resultmessage includes an identifier of the source BSC.
 11. A method forreconnecting an exchange of packet data between a mobile station and anexternal packet network by storing dormant state information of mobilestations in a dormant state where no packet data is exchanged with theexternal packet network, in a centralized database connected to a packetdata switch, and updating the dormant state information stored in thecentralized database in association with the mobile station when themobile station in the dormant state moves to a target BSC adjacent to asource BSC in a wireless packet data system including a packet dataswitch node (PDSN) for connecting the external packet network to themobile stations through the packet data switch and the source BSCconnected to the packet data switch, the method comprising the steps of:upon receipt of a termination call requesting termination of packet datafrom the external packet network, transmitting from the source BSC tothe centralized database a query message for determining a location ofthe mobile station for the termination call; upon receipt of the querymessage, searching dormant state information stored in association withthe mobile station in the centralized database and transmitting thesearched dormant state information to the source BSC using a locationinformation message; upon receipt of the location information message,transmitting from the source BSC to the target BSC where the mobilestation is located a paging request message for requesting paging of themobile station; upon receipt of the paging request message, paging bythe target BSC the mobile station and transmitting a page responseacknowledge message acknowledging the paging to the source BSC when themobile station responds to the paging; upon receipt of the pagingresponse acknowledge message, transmitting from the source BSC to thetarget BSC a packet call connection message requesting connection of thepacket data, and thus connecting the source BSC to the target BSCthrough the packet data switch.
 12. The method as claimed in claim 11,wherein the dormant state information includes an identifier of themobile station, location information of the mobile station, a lastregistration time of the mobile station, and a source BSC ID of themobile station.
 13. The method as claimed in claim 12, wherein thedormant state information includes identifiers for connections used toexchange packet data of the mobile station in the dormant state, atemporary identifier assigned to the mobile station, a service optionand service configuration.
 14. The method as claimed in claim 11,wherein the query message includes an identifier of the mobile stationfor the termination call.
 15. A method for storing dormant stateinformation of mobile stations in a dormant state where no packet datais exchanged with an external packet network, in a centralized databaseconnected to a packet data switch, and updating the dormant stateinformation stored in the centralized database in association with themobile station when the mobile station in the dormant state moves to atarget BSC adjacent to a source BSC in a wireless packet data systemincluding a packet data switch node (PDSN) for connecting the externalpacket network to the mobile stations through the packet data switch andthe source BSC connected to the packet data switch, the methodcomprising the steps of: transmitting to the target BSC a locationregistration message when the mobile station moves to the target BSCadjacent to the source BSC; upon receipt of the location registrationmessage, transmitting from the target BSC to the centralized database alocation update message for updating a location of the mobile station;upon receipt of the location update message, transmitting from thecentralized database to the PDSN a location information update requestmessage for requesting designation of the target BSC as a source BSC;upon receipt of the location information update request message,designating by the PDSN the target BSC as a new source BSC andtransmitting an acknowledge message to the centralized database; andupon receipt of the acknowledge message, updating by the centralizeddatabase the dormant state information for the mobile station by thecentralized database and transmitting a location update result messageindicating complete update of the dormant state information to thetarget BSC.
 16. The method as claimed in claim 15, wherein the dormantstate information includes an identifier of the mobile station, locationinformation of the mobile station, a last registration time of themobile station, and a source BSC ID of the mobile station.
 17. Themethod as claimed in claim 16, wherein the dormant state informationincludes identifiers for connections used to exchange packet data of themobile station in the dormant state, a temporary identifier assigned tothe mobile station, a service option and service configuration.
 18. Themethod as claimed in claim 16, wherein the location update messageincludes an identifier of the mobile station, and location informationof the mobile station.
 19. The method as claimed in claim 18, whereinthe location information of the mobile station is an identifier of thetarget BSC.
 20. A method for reconnecting an exchange of packet databetween a mobile station and an external packet network by storingdormant state information of mobile stations in a dormant state where nopacket data is exchanged with the external packet network, in acentralized database connected to a packet data switch, and updating thedormant state information stored in the centralized database inassociation with the mobile station when the mobile station in thedormant state moves to a target BSC adjacent to a source BSC in awireless packet data system including a packet data switch node (PDSN)for connecting the external packet network to the mobile stationsthrough the packet data switch and the source BSC connected to thepacket data switch, the method comprising the steps of: transmittingfrom the mobile station to the target BSC an origination message forrequesting transmission of packet data; upon receipt of the originationmessage, transmitting from the target BSC to the centralized database adormant information request message for requesting dormant information;upon receipt of the dormant information request message, searching bythe centralized database dormant state information stored in associationwith the mobile station , and transmitting the searched dormant stateinformation to the target BSC using a search result message; and uponreceipt of the search result message, connecting by the target BSC themobile station to the PDSN through the packet data switch based on thedormant state information included in the search result message.
 21. Themethod as claimed in claim 20, wherein the dormant state informationincludes an identifier of the mobile station, location information ofthe mobile station, a last registration time of the mobile station, anda source BSC ID of the mobile station.
 22. The method as claimed inclaim 21, wherein the dormant state information includes identifiers forconnections used to exchange packet data of the mobile station in thedormant state, a temporary identifier assigned to the mobile station, aservice option and service configuration.
 23. The method as claimed inclaim 20, wherein the dormant state information request message includesan identifier of the mobile station, and an identifier of the targetBSC.
 24. A method for reconnecting an exchange of packet data between amobile station and an external packet network by storing dormant stateinformation of mobile stations in a dormant state where no packet datais exchanged with the external packet network, in a centralized databaseconnected to a packet data switch, and updating the dormant stateinformation stored in the centralized database in association with themobile station when the mobile station in the dormant state moves to atarget BSC adjacent to a source BSC in a wireless packet data systemincluding a packet data switch node (PDSN) for connecting the externalpacket network to the mobile stations through the packet data switch andthe source BSC connected to the packet data switch, the methodcomprising the steps of: upon receipt of a termination call requestingtermination of packet data from the external packet network through thePDSN, transmitting from the target BSC to the centralized database, aquery message for determining a location of the mobile station for thetermination call; upon receipt of the query message, analyzing by thecentralized database dormant state information stored in associationwith the mobile station and transmitting the analyzed dormant stateinformation to the target BSC using a location information message; uponreceipt of the location information message, generating by the targetBSC an internal paging request message by the target BSC andtransmitting a page message for paging the mobile station based on thepaging request message; upon receipt of a paging response message fromthe mobile station in response to the page message, generating aninternal paging response acknowledge message and transmitting to thecentralized database a query message for requesting service informationof the mobile station; upon receipt of the query message, transmittingfrom the centralized database to the target BSC the service informationstored in association with the mobile station using a given message; andupon receipt of the service information, transmitting from the targetBSC to the PDSN a packet call connection message for requestingconnection of the packet data and thus connecting the PDSN to the targetBSC through the packet data switch.
 25. The method as claimed in claim24, wherein the dormant state information includes an identifier of themobile station, location information of the mobile station, a lastregistration time of the mobile station, and a source BSC ID of themobile station.
 26. The method as claimed in claim 25, wherein thedormant state information includes identifiers for connections used toexchange packet data of the mobile station in the dormant state, atemporary identifier assigned to the mobile station, a service optionand service configuration.
 27. The method as claimed in claim 24,wherein the query message includes an identifier of the mobile stationfor the termination call.